1. Field of the Invention
This invention relates to a power-supply wiring device, for example disposed in a sliding door of a car, to supply electric power continuously from a vehicle body to the sliding door with absorbing change of wire length between the sliding door and the vehicle body by a stroke to open and close the sliding door, and a harness layout structure by using the power-supply wiring device.
2. Description of the Related Art
Usually, to supply electric power from a vehicle body of a car to car electric devices or auxiliary devices in a sliding door, power-supply wiring device which pulls and pushes a wire harness in a case (harness protector) correspondingly to open/close motion of the sliding door. The case is mounted vertically in the sliding door, and the wire harness (electric wires covered by a protection tube of synthetic resin) is received with curvature in the case and pushed upwardly. One end of the wire harness is disposed at the vehicle body and the other end of the wire harness is disposed at the sliding door (refer the Japan Patent Application 1). When the sliding door is opened from complete closed condition, the sliding door is separated outwardly from the vehicle body and slid two-dimensionally.
Japan Patent Application reference 2 discloses a power-supply wiring device which absorbs change of wire length between the sliding door and the vehicle body corresponding to opening and closing the sliding door by disposing a box-shape case horizontally on the vehicle body and receiving the wire harness (electric wires) spirally in the case.
A power-supply wiring device which disposes electric wires along a convexly formed steel band having directional bending stiffness or a flexible cover having caterpillar shape or the like is proposed. A power-supply wiring device which uses a special electric wire such as a cabtyre cable, a curl electric cord or braided wire is proposed.
References are follows;                Reference 1: Japan Patent Application Laid open 2001-354085, page 7–9, FIGS. 4–7;        Reference 2: Japan Patent Application Laid open 2002-2288, page 2–4, FIG. 1.        
3. Objects to be Solved
However, the aforesaid usual power-supply wiring devices are limited not to place the case at a position interfering with a window glass, a mechanism for moving the window glass up-and-down or electric devices in the sliding door. When the sliding door is opened from complete closed condition, the sliding door is separated outwardly from the vehicle body and slid two-dimensionally, so that motion of the wire harness is complicated and the manufacturing cost may be increased by requiring a suitable flexible wire harness. The power-supply wiring devices are required to use a leaf spring having high durability of bending, or an expensive electric wire cover having directional bending stiffness, so that the structure of the power-supply wiring device is complicated and the manufacturing cost is increased. The wire harness is exposed between the sliding door and the vehicle body so that the wire harness may be deformed by interfering with outside objects or soiled easily. The power-supply wiring device by receiving the wire harness spirally in the case is limited to use a flexible electric wire. The power-supply wiring device by using a special electric wire such as a cabtyre cable or a curl electric cord has a difficulty of changing an electric circuit correspondingly to each car models by limitation of a number of electric wires or wire diameter, and the manufacturing cost may be increased. The power-supply wiring device by receiving electric wires spirally in a horizontal case may require the horizontal case having larger height so that it may be difficult to install the power-supply wiring device at a small room of the vehicle body.
To overcome the above drawback, an object of this invention is to provide a power-supply wiring device for supplying electric power continuously from a fixed structure such as a vehicle body to a sliding structure such as a sliding door with absorbing change of wire length between the sliding structure and the fixed structure by elongating or shortening the electric wire by sliding motion of the sliding structure, which can give two-dimensional smooth sliding motion of opening and closing the sliding structure, and can reduce an installing space of a height of at the sliding structure and the fixed structure, and can simplify structure of the power-supply wiring device without a pushing member such as a leaf spring, and can prevent the wire harness from interference with outside objects, and can correspond to various circuits at a low cost with a normal insulation covered wire, not a special wire, and a harness layout structure by using the power-supply wiring device.